JAJU732C June 2019 – July 2022
Switching frequency is another important design parameter which affects the efficiency and power density of power converter. The input and the output voltage levels primarily determine the type of switches used in the power stage. Usage of SiC MOSFETs in the power stage drives the switching frequencies to very high levels. Operating at higher switching frequencies enables reduced size of magnetics which help in improved thermal solution, thereby improving power density of the converter. Therefore, selection of switching frequency is primarily a tradeoff between the allowable heat sink solution and transformer size for a given efficiency target. Secondly, if the output capacitance (Ecoss) of MOSFET is very high, selection of high switching frequency leads to high switching losses at light load and hampers efficiency. Selection of switching frequency also affects the control loop bandwidth implementation. Considering all of these parameters, 100 kHz was used as the switching frequency for this application.